Barrier systems are used in a number of applications for blocking or redirecting movement of vehicles and similar objects, and, in the process of doing so, absorbing some amount of the vehicle's kinetic energy. There are numerous examples of barrier systems--for example, steel guard rails, concrete wall dividers, arrays of barrels and plastic shells filled with water or sand. Steel guard rails and concrete wall dividers are intended primarily to redirect a vehicle, such as away from oncoming traffic or from perils along side a road, not to absorb much of the kinetic energy of a moving vehicle upon impact. Thus, they tend to be used where head-on impacts are unlikely. Furthermore, they are very strong and withstand impacts. It is the vehicle that tends to absorb the brunt of the impact with such a barrier. On the other hand, barrel arrays and water-filled plastic shells are intended to permanently deform in order to absorb substantial amounts of kinetic energy, especially in a progressive manner in order to slow a vehicle to a stop without causing mortal injury to the occupants of the vehicle. They are used in situations where head-on impacts are more likely, especially where there exists obstructions such as bridge embankments and pillars that would cause significant damage to a vehicle hitting it. Both the vehicle and the barrier suffer significant damage during impact.
During impacts involving relatively high kinetic energies, these types of barriers or the vehicles, or both, tend to be permanently damaged. Generally, all such barriers tend to rely on the vehicle to absorb some of the energy, primarily through deformation. Indeed, during lower speed impacts, it is the vehicle that is intended to suffer most of the damage, primarily through deformation. Consequently, these barriers are acceptable for roads and highways since automobiles are not expected to frequently impact them. However, in situations where impacts are much more likely, either more resilient systems or less expensively and more quickly repaired systems are desirable.
An example of one such situation is a go-kart track, especially one used for amusement rather than sport racing purposes. Barriers traditionally used on roads are generally unacceptable for use on such amusement tracks. Amusement-type go-kart tracks, especially the type featuring many turns, require resilient systems that will absorb a significant amount of kinetic energy of the vehicle at lower speeds. Patrons of amusement parks will tend to crash into barriers more frequently. Damage to the vehicle and the barrier is therefore to be avoided. Thus, the speed of the vehicles are kept somewhat low, and resilient barrier systems on the track and resilient bumper systems on the vehicles are used to absorb kinetic energy during impact with a barrier without damaging the vehicle or track. One example of such a resilient barrier system is a line of tires, or portions thereof, laid end-to-end around the track, flat against the ground. An exterior side of the tires abut a curb or other fixed vertical structure, or alternately, each of the tires is anchored to the ground. The tires act like springs, absorbing and, to some degree, dissipating kinetic energy while remaining resilient. To prevent a vehicle from grabbing a tire during a glancing impact, a thin band of steel or other material lines the inside edge of the tires, opposite the curb, to create a flexible steel wall against which vehicles may easily glance.
Such a system is acceptable for relatively low-velocity vehicles, especially where they cannot easily crash into a barrier head-on. However, newer amusement tracks desire to more closely simulate real racing experiences, using heavier vehicles that operate at higher speeds. Prior art systems tend not to exhibit desirable energy absorption characteristics: they are either not sufficiently elastic or sufficiently strong enough.